﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Web;
using System.Web.SessionState;

namespace AFT.Parking.Foundation
{
    public class VerifyCode : IHttpHandler, IRequiresSessionState
    {
        public void ProcessRequest(HttpContext context)
        {
            //string code = CreateVerifyCode();
            //CreateImageOnPage(code, context);
            string code = GenerateCheckCode();
            CreateCheckCodeImage(code, context);
            context.Session["VerifyCode"] = code;
        }

        public bool IsReusable
        {
            get { return true; }
        }

        private string GenerateCheckCode()
        {
            int number;
            char code;
            string checkCode = String.Empty;

            System.Random random = new Random();

            for (int i = 0; i < 5; i++)
            {
                number = random.Next();

                if (number % 2 == 0)
                    code = (char)('0' + (char)(number % 10));
                else
                    code = (char)('A' + (char)(number % 26));

                checkCode += code.ToString();
            }

            //Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));

            return checkCode;
        }

        private void CreateCheckCodeImage(string checkCode, HttpContext context)
        {
            if (checkCode == null || checkCode.Trim() == String.Empty)
                return;

            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 20.5)), 40);
            Graphics g = Graphics.FromImage(image);

            try
            {
                //生成随机生成器
                Random random = new Random();

                //清空图片背景色
                g.Clear(Color.White);

                //画图片的背景噪音线
                for (int i = 0; i < 25; i++)
                {
                    int x1 = random.Next(image.Width);
                    int x2 = random.Next(image.Width);
                    int y1 = random.Next(image.Height);
                    int y2 = random.Next(image.Height);

                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                }

                Font font = new System.Drawing.Font("Arial", 22, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                g.DrawString(checkCode, font, brush, 2, 2);

                //画图片的前景噪音点
                for (int i = 0; i < 100; i++)
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);

                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }

                //画图片的边框线
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

                System.IO.MemoryStream ms = new System.IO.MemoryStream();
                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                context.Response.ClearContent();
                context.Response.ContentType = "image/Gif";
                context.Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }

        #region 生成验证码相关属性值

        private const double PI = 3.1415926535897932384626433832795;
        private const double PI2 = 6.283185307179586476925286766559;

        private int _Length = 5;//验证码长度(默认6个验证码的长度)
        private int _FontSize = 50;//验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)
        private int _Padding = 1;//边框补(默认1像素)
        private bool _Chaos = true;//是否输出燥点(默认不输出)
        private Color _ChaosColor = Color.Red;//输出燥点的颜色(默认灰色)
        private Color _BackgroundColor = Color.FromArgb(255, 242, 242, 242);//自定义背景色(默认白色)
        private Color[] _Colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };//自定义随机颜色数组
        private string[] _Fonts = { "Arial", "Verdana" };//自定义字体数组
        private string _CodeSerial = "2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,k,m,n,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,K,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";//自定义随机码字符串序列(使用逗号分隔)

        public int Length
        {
            get { return _Length; }
            set { _Length = value; }
        }
        public int FontSize
        {
            get { return _FontSize; }
            set { _FontSize = value; }
        }
        public int Padding
        {
            get { return _Padding; }
            set { _Padding = value; }
        }
        public bool Chaos
        {
            get { return _Chaos; }
            set { _Chaos = value; }
        }
        public Color ChaosColor
        {
            get { return _ChaosColor; }
            set { _ChaosColor = value; }
        }
        public Color BackgroundColor
        {
            get { return _BackgroundColor; }
            set { _BackgroundColor = value; }
        }
        public Color[] Colors
        {
            get { return _Colors; }
            set { _Colors = value; }
        }
        public string[] Fonts
        {
            get { return _Fonts; }
            set { _Fonts = value; }
        }
        public string CodeSerial
        {
            get { return _CodeSerial; }
            set { _CodeSerial = value; }
        }

        #endregion

        #region 生成随机字符码
        public string CreateVerifyCode()
        {
            string[] verifyCodeList = this.CodeSerial.Split(',');
            Random random = new Random(unchecked((int)DateTime.Now.Ticks));
            System.Text.StringBuilder stringBuilder = new System.Text.StringBuilder();
            for (int i = 0; i < this.Length; i++)
            {
                int randomValue = random.Next(0, verifyCodeList.Length - 1);
                stringBuilder.Append(verifyCodeList[randomValue]);
            }
            return stringBuilder.ToString();
        }

        #endregion

        #region 将创建好的图片输出到页面

        public void CreateImageOnPage(string code, HttpContext context)
        {
            System.IO.MemoryStream memoryStream = new System.IO.MemoryStream();
            Bitmap image = CreateImageCode(code);

            image.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Jpeg);

            context.Response.ClearContent();
            context.Response.ContentType = "image/Jpeg";
            context.Response.BinaryWrite(memoryStream.GetBuffer());

            memoryStream.Close();
            memoryStream = null;
            image.Dispose();
            image = null;
        }

        #endregion

        #region 生成校验码图片

        public Bitmap CreateImageCode(string code)
        {
            int fSize = this.FontSize;
            int fWidth = fSize + this.Padding;
            int imageWidth = (int)(code.Length * fWidth) + 4 + this.Padding * 2;
            int imageHeight = fSize * 2 + this.Padding;

            Bitmap image = new Bitmap(imageWidth, imageHeight);
            Graphics g = Graphics.FromImage(image);
            g.Clear(this.BackgroundColor);

            Random rand = new Random();
            //给背景添加随机生成的燥点
            if (this.Chaos)
            {
                Pen pen = new Pen(this.ChaosColor, 0);
                int c = this.Length * 10;
                for (int i = 0; i < c; i++)
                {
                    int x = rand.Next(image.Width);
                    int y = rand.Next(image.Height);

                    g.DrawRectangle(pen, x, y, 1, 1);
                }
            }

            int left = 0, top = 0, top1 = 1, top2 = 1;
            int n1 = (imageHeight - this.FontSize - this.Padding * 2);
            int n2 = n1 / 4;
            top1 = n2;
            top2 = n2 * 2;
            Font f;
            Brush b;
            int cindex, findex;

            //随机字体和颜色的验证码字符
            for (int i = 0; i < code.Length; i++)
            {
                cindex = rand.Next(this.Colors.Length - 1);
                findex = rand.Next(this.Fonts.Length - 1);
                f = new System.Drawing.Font(this.Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
                b = new System.Drawing.SolidBrush(this.Colors[cindex]);

                if (i % 2 == 1)
                {
                    top = top2;
                }
                else
                {
                    top = top1;
                }

                left = i * fWidth;

                g.DrawString(code.Substring(i, 1), f, b, left, top);
            }

            //画一个边框 边框颜色为Color.Gainsboro
            g.DrawRectangle(new Pen(Color.White, 0), 0, 0, image.Width - 1, image.Height - 1);
            g.Dispose();

            //产生波形（Add By 51aspx.com）
            image = TwistImage(image, true, 20, 1);

            return image;
        }

        #endregion

        #region 生成波形滤镜效果

        /// <summary>
        /// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
        /// </summary>
        /// <param name="srcBmp">图片路径</param>
        /// <param name="bXDir">如果扭曲则选择为True</param>
        /// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
        /// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
        /// <returns></returns>
        public Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
        {
            Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);

            // 将位图背景填充为白色
            Graphics graph = Graphics.FromImage(destBmp);
            graph.FillRectangle(new SolidBrush(Color.White), 0, 0, destBmp.Width, destBmp.Height);
            graph.Dispose();

            double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

            for (int i = 0; i < destBmp.Width; i++)
            {
                for (int j = 0; j < destBmp.Height; j++)
                {
                    double dx = 0;
                    dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
                    dx += dPhase;
                    double dy = Math.Sin(dx);

                    // 取得当前点的颜色
                    int nOldX = 0, nOldY = 0;
                    nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
                    nOldY = bXDir ? j : j + (int)(dy * dMultValue);

                    System.Drawing.Color color = srcBmp.GetPixel(i, j);
                    if (nOldX >= 0 && nOldX < destBmp.Width
                     && nOldY >= 0 && nOldY < destBmp.Height)
                    {
                        destBmp.SetPixel(nOldX, nOldY, color);
                    }
                }
            }

            return destBmp;
        }

        #endregion
    }
}
